Related Mcqs:

1. A semi-circular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi-cricular disc and horizontal surface is \i. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will____________________?

   A. remain horizontal
   B. slant up towards direction of pull
   C. slant down towards direction of pull
   D. unpredictable
   E. none of the above

2. Dynamic friction as compared to static friction is___________________?

   A. same
   B. more
   C. less
   D. may be less of more depending on nature of surfaces and velocity
   E. has no correlation

3. Coulomb friction is the friction between _________________?

   A. bodies having relative motion
   B. two dry surfaces
   C. two lubricated surfaces
   D. solids and liquids
   E. electrically charged particles

4. The resultant of the following three couples 20 kg force, 0.5 m arm, $ ve sense 30 kg force, 1 m arm, – ve sense 40 kg force, 0.25 m arm, + ve sense having arm of 0.5 m will be__________________?

   A. 20 kg, – ve sense
   B. 20 kg, + ve sense
   C. 10 kg, + ve sense
   D. 10 kg, – ve sense
   E. 45 kg, + ve sense

5. Limiting force of friction is the__________________?

   A. tangent of angle between normal-reaction and the resultant of normal reaction and limiting friction
   B. ratio of limiting friction and normal reaction
   C. the friction force acting when the body is just about to move
   D. the friction force acting when the body is in motion
   E. minimum force of friction

6. On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be_________________?

   A. downwards at its upper end
   B. upwards at its upper end
   C. perpendicular to the wall at its upper end
   D. zero at its upper end
   E. none of the above

7. Least force required to draw a body up the inclined plane is W sin (plane inclination + friction angle) applied in the direction___________________?

   A. along the plane
   B. horizontally
   C. vertically
   D. at an angle equal to the angle of friction to the inclined plane
   E. unpredictable

8. On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be___________________?

   A. towards the wall at its upper end
   B. away from the wall at its upper end
   C. upwards at its upper end
   D. downwards at its upper end
   E. none of the above

9. The unit of force in S.I. units is________________?

   A. kilogram
   B. newton
   C. watt
   D. dyne
   E. joule

10. The co-efficient of friction depends upon_______________?

    A. nature of surfaces
    B. area of contact
    C. shape of the surfaces
    D. ail of the above.
    E. A. and B. above